/* SCD - Slowly Changing Dimension - Type 3 - State dimension           */ 
/* Region for "New Jersey" and "Alaska" changed - A prev column is used */

select * from state;

select * from state 
where region != region_prev;


/* Display total tax collected by state */

select state_name, sum(tax) 
from payment join state using (state_code)
group by state_name with rollup;


/* Display total tax collected by current region and state */

select region, state_name, sum(tax), max(region_prev) "prev region"
from payment join state using (state_code)
group by region, state_name with rollup;


/* Display total tax collected by previous region and state */

select region_prev, state_name, sum(tax), max(region) "curr region"
from payment join state using (state_code)
group by region_prev, state_name with rollup;